9 ms·

Cryptographic attacks become better, some of them become practical. RC4 attacks were not considered practical until recently, and now everyone runs with their h

by dchest 11y ago

Cryptographic attacks become better, some of them become practical. RC4 attacks were not considered practical until recently, and now everyone runs with their heads on fire replacing it. The best answer is to listen to what security people say. When they have a practical attack on something it is already too late.

Touche 11y ago
Security experts, by in large, only care about academics and care very little about usability, so I do not trust them unless they give me specific scenarios where I am in danger.
- dchest 11y ago
  Eh, okay? Your choice, dear Touche, your choice.
  - Touche 11y ago
    Just to clarify what I mean; we have to make decisions based on tradeoffs. Having the most secure password possible is not the only thing that matters. So "trust security experts" is not a good response; I need to know threat levels so I can make informed decisions. I'm not just going to do the same thing a security enthusiast does because I value different things, to different degrees.
    - dchest 11y ago
      Looks like you didn't understand the sadness of the issue I was reporting. The author of the software constructed his own random number generator from two primitives: Salsa20 stream generator and Math.random. The last part is what makes this PRNG theoretically insecure: because Math.random is not guaranteed to give cryptographically secure random numbers, thus, theoretically, the generated passwords can be guessed. (The fact that there are no current attacks on current implementations of Math.random in browsers doesn't mean that we won't get them in the future.) The secure alternative to author's PRNG is ~one line of code: window.crypto.getRandomBytes. There are no tradeoffs involved! On the contrary, the author's insecure construction is more difficult to write than the secure one. (BTW, while we here argue about security experts, the author said "Thank you, I'll replace it of course.")
      - Touche 11y ago
        This is what I'm talking about. You, a security enthusiast, are only interested in the technical security details. You respond to a comment about tradeoffs with details on the bug. I don't care about why the bug happened or how easy it is/isn't to fix. I care about whether the existence of the bug is something I should be so concerned about as to not use the software. In order to gauge that, I need a little more info about the threat level.
        Nadya 11y ago
        >I don't care about why the bug happened or how easy it is/isn't to fix. I care about whether the existence of the bug is something I should be so concerned about as to not use the software. In order to gauge that, I need a little more info about the threat level. Threat level is 0%. No currently known attacks exist. This threat level immediately goes to 100% when a practical attack is discovered. There is no guarantee that a practical attack exists that hasn't been brought to academic or mainstream attention (e.g some cracker has a practical attack that they're keeping under wraps). By the time the threat level hits 100% the cracker may have already broken into your account(s) before you even hear about the attack. Therefore when something is shown that "attacking it is possible" you can make one of two assumptions 1) No practical attack exists and you'll be safe until it exists 2) A practical attack already exists and it is only a matter of time until you get pwned Rather than worry about whether or not a practical attack already or will one day exist, I'd use cryptography that hasn't been shown to be broken.
        Touche 11y ago
        This comment doesn't make sense. All attacks are not equal. Some require physical access; some do not. Some require seed data; some do not. What exactly are you talking about here? This is why security people are so frustrating to talk to; you only talk in extremes. > Rather than worry about whether or not a practical attack already or will one day exist, I'd use cryptography that hasn't been shown to be broken. That's not what I'm worried about. I'm worried about given that they do exist what is the risk to me? What is the likelihood that my account has been broken into?

by dchest 11y ago

Touche 11y ago

Security experts, by in large, only care about academics and care very little about usability, so I do not trust them unless they give me specific scenarios where I am in danger.

dchest 11y ago
Eh, okay? Your choice, dear Touche, your choice.
- Touche 11y ago
  Just to clarify what I mean; we have to make decisions based on tradeoffs. Having the most secure password possible is not the only thing that matters. So "trust security experts" is not a good response; I need to know threat levels so I can make informed decisions. I'm not just going to do the same thing a security enthusiast does because I value different things, to different degrees.
  - dchest 11y ago
    Looks like you didn't understand the sadness of the issue I was reporting. The author of the software constructed his own random number generator from two primitives: Salsa20 stream generator and Math.random. The last part is what makes this PRNG theoretically insecure: because Math.random is not guaranteed to give cryptographically secure random numbers, thus, theoretically, the generated passwords can be guessed. (The fact that there are no current attacks on current implementations of Math.random in browsers doesn't mean that we won't get them in the future.) The secure alternative to author's PRNG is ~one line of code: window.crypto.getRandomBytes. There are no tradeoffs involved! On the contrary, the author's insecure construction is more difficult to write than the secure one. (BTW, while we here argue about security experts, the author said "Thank you, I'll replace it of course.")
    - Touche 11y ago
      This is what I'm talking about. You, a security enthusiast, are only interested in the technical security details. You respond to a comment about tradeoffs with details on the bug. I don't care about why the bug happened or how easy it is/isn't to fix. I care about whether the existence of the bug is something I should be so concerned about as to not use the software. In order to gauge that, I need a little more info about the threat level.
      - Nadya 11y ago
        >I don't care about why the bug happened or how easy it is/isn't to fix. I care about whether the existence of the bug is something I should be so concerned about as to not use the software. In order to gauge that, I need a little more info about the threat level. Threat level is 0%. No currently known attacks exist. This threat level immediately goes to 100% when a practical attack is discovered. There is no guarantee that a practical attack exists that hasn't been brought to academic or mainstream attention (e.g some cracker has a practical attack that they're keeping under wraps). By the time the threat level hits 100% the cracker may have already broken into your account(s) before you even hear about the attack. Therefore when something is shown that "attacking it is possible" you can make one of two assumptions 1) No practical attack exists and you'll be safe until it exists 2) A practical attack already exists and it is only a matter of time until you get pwned Rather than worry about whether or not a practical attack already or will one day exist, I'd use cryptography that hasn't been shown to be broken.
        Touche 11y ago
        This comment doesn't make sense. All attacks are not equal. Some require physical access; some do not. Some require seed data; some do not. What exactly are you talking about here? This is why security people are so frustrating to talk to; you only talk in extremes. > Rather than worry about whether or not a practical attack already or will one day exist, I'd use cryptography that hasn't been shown to be broken. That's not what I'm worried about. I'm worried about given that they do exist what is the risk to me? What is the likelihood that my account has been broken into?